An Iowa City hospital is warning patients that some of their personal information may have been accessed through a computer virus.

The Iowa City Press-Citizen reports an investigation revealed that a computer virus that is designed to capture personal data had infected some computers in January at Mercy Iowa City and Mercy Clinics.

The potentially stolen information may have included patient demographics such as addresses, clinical information such as treatments and medications or health insurance information.

Officials say that in some cases Social Security numbers may have been accessed.

There is no evidence that any patient information has been used improperly and hospital officials mailed letters to affected patients Friday.

Mercy continues to investigate the privacy breach with the help of law enforcement.